Weaving machines



Jan. 18, 1966 HIFUMI sAl'ro WEAVING MACHINES 6 Sheets-Sheet 1 Filed Feb. 5, 1964 INVENTOR -'FUMI 5917.0

ATTORNEYS- Jan. 18, 1966 HlFUMl SAITO WEAVING MACHINES 6 Sheecs-Sheecl 2 Filed Feb. 5, 1964 INVENTOR Hl'F .mi SHI TC ATTORNEY;

Jan. 18, 1966 HlFUMl sAn-o WEAVING MACHINES 6 Sheets-Sheet 5 Filed Feb. 3, 1964 INVENTOR f TC ATTORNEYS m 1%? 196% H1FUM| sAlTo 3,229,725

WEAVING MACHINES Filed Feb. 5, 1964 6 Sheecs-Sheeil 4 INV ENTOR 3am., 1S, E966 HIFUMI sAl'ro WEAVING MACHINES 6 Sheets-Sheet 5 Filed Feb. 5, 1964 INVENTOR [Fim SHI T0 ATTORNEYS Jam. i8, 1966 HlFuMl sAlTo WEAVING MACHINES 6 Sheets-Shea?l 6 Filed Feb. 5, 1964 INVENTOR ATTORNEY5 United States Patent O 3,229,725 WEAVING MACHINES Hifumi Saito, 14-10 Nalrasuji, Haruemachi, Sakai-gun, Futuri-ken, Japan Filed Feb. 3, 1964, Ser. No. 341,928

Claims priority, application japan, Feb. 6, 1963, IIS/6,371, Sti/6,372; Feb. 21, 1963, :iS/9,065; .Iune 13, 1963, .3S/31,640; Oct. 5, 1963, $853,580,

Sti/53,581; Nov. 29, 1963, 38/64,372

14 Claims. (Cl. 139-127) This invention relates to so-called jet looms or weaving machines in which weft or filling yarns are picked by jets of fluid under pressure. Previously known air jet looms employ relatively high air pressures giving rise to explosive sounds when jets are formed and are generally unable to weave into fabric fine yarns, particularly, single yarns comprising short fibers and yarns comprising rayon, acetate or other long fibers. Water jet looms are capable of weaving tine yarns but are hardly capable of weaving raw yarns which are hydrophilic or of weaving fabrics which employ warp yarns to be perfectly sized. After all, the fact is that there are many kinds of Woven fabric which cannot be formed by any of existing air or water jet looms.

The present invention is concerned particularly with jet looms employing air as pressure lliuid and proposes to ernploy extraordinarily low air pressures to make it possible to weave those kinds of fabric which it has previously been impossible to weave with jet looms as well as fabrics of the kind previously weavable thereon. Use of low air pressures is also advantageous in that it reduces cost of air and eliminates occurrence of explosive sounds upon jet formation and warp damage due to jet currents, as will readily be understood from the following description.

It has been known in weaving fabric by the aid of pressure air to employ auxiliary blasts midway of the weft passage for the purpose of helping liiight of weft yarns. Such auxiliary blasts have also been tentatively employed with Water jet looms to make it possible to weave fabrics of increased widths thereon. Previous auxiliary blast devices, however, have been incompetent to weave fabric with rayon, acetate or other long fibers or with single yarns of staple fiber which tends to untwist and ravel to break. With air jet looms, means for preventing untwist of filling yarns at the outlet of the air nozzle have been devised but are not completely satisfactory yet. For example, with a certain known nozzle mechanism, adapted to fly No 4() singles of staple fiber over a distance of one meter or over, it has been found that yarn frequently breaks due to untwist when ejected Iby air pressure of the order of 0.3 kg./cm.2 and this necessitates use of lower air pressures in weaving such yarn into fabric. Under this situation, desperate efforts must be made in order to reduce the air pressure even slightly, for example, by only an amount of 0.1 kg./cm.2 In addition, for weaving with such lower air pressure, it is necessary to employ a well-designed advanced auxiliary blast means midway of the weft passage and it is important to extend the duration of air ejection as required. Extension of the duration of air ejection means that the ejection is started earlier at the time when the shed is still very small and the filling yarn must be inserted while avoiding its contact with the warp yarns as far as possible. Moreover, the picking operation must be effected in such a manner as to reduce or eliminate any shock, resistance or obstacle to the filling yarn being inserted.

The present invention has solved all of the above problems previously met with yjet looms.

The present invention will now be described with reference to the accompanying drawings, in which:

F'IG. 1 is a diagrammatic rear View of a jet loom embodying the present invention;

ICC

FIG. 2 is a fragmentary perspective rear view illustrating the mechanism for moving back and forth the air nozzle for weft insertion;

FIG. 3 is a side elevation of the mechanism shown in FIG. 2;

FIG. 4A is a fragmentary schematic view illustrating the relative position of the shed and the air nozzle according to the present invention at the start of air ejection;

FIG. 4B is a View generally similar to FIG. 4A illustrating the position of the air nozzle conventionally secured to the reed frame at the same instant as in FIG. 4A;

FIGS. 5C and 5D are fragmentary plan views illustrating the relative position of the air nozzle for weft insertion with its yarn inlet and the mechanism for furnishing yarn thereto; FIG. SC illustrates the air nozzle secured to the reed frame for movement therewith, and FIG. SID illustrates the air nozzle arranged not only for movement with the battening motion of the reed but also for movement relative to the plane of the reed frame; in these gures, reference characters C-I and D-1 represent the nozzle position when the shed is at its Imaximum and reference characters C-Z and D-2 represent the nozzle position when the weft yarn has been pushed against the formed portion of the fabric;

FIGS. 6E and 6F are schematic plan views showing the relationship between the auxiliary blast arrangement and the path of weft yarn being ejected through respective air nozzles int-o which the weft is introduced in different ways;

FIGS. 6E-1 and 6F-1 are cross-sectional views taken along the line X-Y in FIGS. 6E and 6F, respectively;

FIG. 7 is a fragmentary perspective view of the weft measuring device;

FIG. 8 is a side view of same showing the operation of the pay-out roller;

FIG. 9 illustrates two forms of annular belt to be fitted over the measuring drum to vary its effective diameter;

FIG. 1() is a vertical cross-sectional View of another basic form of weft measuring device;

FIG. 11 is a front View of the essential part of the weft measuring device of FIG. 10;

FIGS. 12 and 13 are a diagrammatic vertical crosssectional view and a front view, respectively, of a further form of weft measuring device;

FIG. 14 is a front view of yet another form of weft measuring device;

FIG. 15 is a perspective view of the weft nipper device; v

FIG. 16 is a side view showing the manner in which the weft nipper device operates;

FIG. 17 is a fragmentary transverse cross-sectional view of the auxiliary blast arrangement;

FIG. 18 is a fragmentary longitudinal cross-sectional View of same; and

FIGS. -191 and 19] are fragmentary vertical crosssectional views of the shielding device when the shed is at its maximum and when reduced.

Referring to the drawings and first to FIG. 1, the weft or filling yarn being fed from a spool 1 is measured by the measuring device 2 and then directed into the main nozzle 3 to be inserted into the shed by a jet of air under pressure formed through the main nozzle and jets of air under pressure formed through auxiliary nozzles 8, 8', which are fed through conduit 57. The weft is subsequently battened and cut by scissors 62. This process is principally the same as with conventional jet looms, but an important feature of the jet loom of the present invention is that it is arranged so that the air nozzle for weft insertion is not only moved back and forth of the loom with the movement of the reed but also the axis of the air nozzle is moved relative to the plane of the reed during the back and forth movement with the reed.

It is conventional to move the air nozzle back and forth of the loom together with the reed. The conventional back and forth movement of the air nozzle is desirable in that the timing for ejecting weft yarn is adjustable to a more or less extent as desired and that, where auxiliary blast means are provided, weft yarns can be inserted under favorable conditions with the main and auxiliary air jets arranged substantially along a straight line. However, the duration of air ejection cannot be extended to any substantial extent with the arrangement in which the main air nozzle is movable only with the reed. More specifically, since the axis of the air nozzle is ordinarily spaced more or less from the reed plane, the nozzle outlet must assume a position where the two groups of warp yarns forming the shed are spaced apart from each other only an extremely limited distance if the duration of air ejection were to be extended. This apparently would increase the tendency for the warp yarns to be damaged and for the yarns ejected to be caught by the warp yarns. Accordingly, with such arrangement, weft yarns must be ejected after a substantial shed has been opened, though the duration of air ejection is limited to that extent. According to the present invention, the arrangement for air ejection is made so that the ejection can be started when the shed is only partly opened. This this end, the nozzle is positioned at the start of ejection in a position immediately adjacent the reed plane and immediately displaced to an optimum position more or less spaced from the plane of the reed. With this arrangement, it will be understood that the duration of air ejection can be extended to a substantial extent since the yarn is inserted through the Widest portion of the warp shed even if the latter is relatively limited. It will be apparent that this design principle is also applicable to the end of air ejection.

Such positioning of the air nozzle will now be described in further detail with reference to FIGS. 2 and 3.

A wheel member 37 is tted over a rock shaft 38, which is driven through a crank mechanism to rock in direct proportion to the crank member. A chain sprocket Wheel 56 is also mounted on the rock shaft to effect the same rotary movement as that of member 37 to drive another sprocket wheel 36 so that shaft 54 secured to the slaysword 39 is rocked in direct proportion to the crank member. A cam 45 is mounted on the shaft 54. The air nozzle 3 is secured to one extremity of a rod 41, which is fulcrumed at 42 on the slay-sword 39 and formed integral with a lever 43. The remote end of the lever 43 is held in sliding contact with a cam by a spring 44. Reference numerals 6 and 6 indicate the bottom and top frames of the reed 9, respectively. In operation, when the raised portion of the cam 45 is out of contact with the lever 43, the nozzle 3 is closely adjacent to the plane of the reed and a filling yarn is being picked with the air ejection through the nozzle 3 interrupted. As the raised portion of the cam 45 starts to actuate the lever 43, the nozzle 3 starts to move forwardly of the reed while initiating weft ejection. When the cam 45 has nearly ceased to act, the weft ejection also comes close to its end. In other words, the air nozzle starts to move to a position best suited to weft ejection simultaneously with the start of the weft ejection and after remaining in that position for a time the nozzle returns to its initial position about the time when the weft ejection terminates. It will be noted that, because of such movement of the air nozzle, which allows the air ejection to be started at the widest point of the shed or closely adjacent to the reed plane, the shed opening can be fully utilized to extend the ejection time. FIG. 4A illustrates the relative position of the warp shed and the air nozzle arranged for movement according to the present invention at the start of ejection, and FIG. 4B illustrates the position of a conventional air nozzle secured to the reed frame for movement therewith when the warp shed is in the same condition as in FIG. 4A. With the nozzle positioned as in FIG. 4B, ejection of air is impossible with any satisfactory results. It will be evident that the positioning of the nozzle 3 in FIG. 4A has many advantages over that in FIG. 4B though the shed or opening between warp groups 10 and the reed position are the same in the two illustrations.

Another advantage of the present invention over previous nozzle arrangements in which the nozzle is secured to the reed for back and forth movement therewith is that no excessive tension is applied to the weft yarn when battened since the axis of the nozzle is then substantially in the plane of the reed. FIG. 5C illustrates the battening position of the reed on conventional jet looms in which the air nozzle is movable with the reed, and FIG. 5D illustrates the battening position of the reed according to the present invention. In these figures, reference characters C-1 and D-1 indicate the nozzle position when the warp yarns are opened to the maximum, While reference characters C-2 and D-2 indicate the nozzle position at the time when the weft yarn has been battened. As observed, the weft yarn 4 is flexed at the nozzle position C-2 in FIG. 5C to a larger extent than at the nozzle position D-Z in FIG. 5D, and such yarn flexure occurs in most cases after the weft yarn has been interlaced with the warp yarns and thus causes an excessive tension in the weft. Separate means may apparently be provided for feeding an appropriate additional length of weft yarn to compensate for such tension, but this renders the loom structure complicated to that extent. It is also to be understood that in some instances it is structurally desirable to have the nozzle positioned adjacent to the reed plane at the time when the weft is pushed against the formed portion of the fabric.

Though in the above illustration the nozzle is carried in a back and forth movement on a rod fulcrumed on the slay-sword, the nozzle can be arranged in various ways as long as the nozzle is movable back and forth in a manner so that the axis of the nozzle is displaced relative to the reed plane to vary the distance therebetween.

A further important feature of the present invention is the relationship of the nozzle structure with the yarn feed to the nozzle and with the auxiliary blasts. The weft ejecting nozzle according to the present invention is constructed so that when ejected through the nozzle, the weft yarn is carried along a path displaced toward the reed from the nozzle axis. As clearly observed in FIGS. 6E, 6F, 6E-l and 6F1, the weft yarn leaves the nozzle exit along a line offset from the nozzle axis to the reed side and thus tends to be deflected away from the axis of the main jet toward the reed. This mode of flight of weft yarns is advantageous in various ways. First, the weft yarn effectively prevented from engagement with warp yarns even if the shed is limited since the weft yarn when ejected through such shed starts to fly along a path adjacent to the reed surface, never deviating toward the Weaving end of the fabric. Secondly, the weft yarn can be blown straight forwardly by the cooperation with the main air jet of auxiliary air blasts which are formed adjacent to the reed surface in the direction of the weft flight so as to be effective to keep the weft from contacting the reed, as shown in FIGS. 6E and 6F. With this arrangement, the weft yarn can pass freely through the shed along the reed surface without contacting the latter. It will be apparent t-o 4those skilled in the lart that the same :effect can he obtained with the nozzle arrangement in which the main nozzle is not movable relative to the reed during the battening operation.

In FIG. 6E, the main nozzle 3 has a yarn inlet aperture 11 formed in its side adjacent to the reed and the auxiliary nozzles have respective exit openings at 8. The position of the yarn 4 in the exit opening of the main nozzle 3 is illustrated in the cross-sectional view of FIG. E-l. FIGS. F and F-l illustrate in plan and in cross section, respectively, a modified form of main air nozzle operable tto the ysame effect as rthe nozzle in FIGS. E and E-l.

For causing the weft yarn to proceed along a path shifted toward the reed surface, it has been a known measure to arrange an additional air nozzle in parallel with the main air nozzle on its side closer to the Weaving end of the fabric. This measure, however, is widely different in effect from the inventive nozzle arrangement and is even detrimental in case ejection is made when the shed of warp yarns is lifted, since the jet from the additional nozzle acts to blow the warp yarns. Incidentally, with the inventive nozzle arrangement, it is apparent that the position of the auxiliary nozzles should be slightly adjusted forwardly or backwardly in accordance with the density of the reed in order to control the amount of auxiliary air that escapes through the reed.

Another important point of nozzle design is the location of the weft inlet to the main nozzle or where and how to feed weft to the main nozzle. According to the present invention, weft is fed to the nozzle from a point located rearwardly of the weft inlet to the nozzle in its rearmost or retracted position, or it is fed to the nozzle, which moves back and forth, from a point behind one extension of the reed plane, as clearly shown in FIGS. l, 5C and 5D. In FIGS. 5C and 5D, reference characters C-l and D-l illustrate the relative position of the reed 9 and nozzle 3 to the yarn exit 17 from the measuring device when the nozzle is in its rearmost position or when the warp shed is at its maximum. As shown, the yarn exit 17 is arranged rearward of the nozzle position indicated by C-l or D-l. This arrangement is highly advantageous in that it facilitates supply of weft yarn to a nozzle which has a yarn inlet aperture on its side adjacent to the reed as shown in FIG. 6E and that the weft yarn is directly fed from the measuring device into the nozzle inlet with no yarn guides arranged therebetween which may provide resistance to the yarn. A further advantage of this arrangement is that because of the yarn feed to the nozzle from behind, the yarn is automatically drawn back as the nozzle is advanced.

It is generally required with air jet looms to slightly draw back the weft yarn once inserted before it is pushed against the solid cloth. To do this, it has been necessary to employ a number of yarn guides, which causes a violent motion or jerk to the yarn. For example, with a known drawback device in which the weft yarn is drawn back by pulling the yarn leg between two guides into an equilateral angular formation, a number of yarn guides are needed and the yarn is instantaneously drawn back by a length substantially corresponding to twice the yarn length forming each side of the angular formation. Such instantaneous motion of the weft yarn causes a violent tremble of the leading end thereof, which often results in a mispick even with auxiliary blasts.

According to the present invention, however, the picked weft is drawn back by the advance of the main nozzle, as observed in FIGS. 5C and 5D. In FIG. 5D, the length of the yarn leg between the yarn exit I7 of the measuring device to the yarn inlet aperture 11 in the air nozzle when the warp shed is at its maximum differs from that when the inserted yarn has been beaten up. This length difference substantially corresponds to the amount of back draw of the weft. Also, the weft is drawn back relatively smoothly in correspondence to the battening speed and is made straight without any quiver at the yarn end. Moreover, the weft yarn is subjected to no resistance inherently provided by yarn guides. With such arrangement, it will be appreciated that weft yarn can be smoothly inserted through the shed of warp yarns by means of a jet of air at extraordinarily low pressure without adversely affecting the short-fiber single or long lament forming the weft yarn. Such feature is based upon a principle similar to that of kite-frying, in which the kite swings when the wind is too strong or the string is suddenly pulled and falls down when the string is made too loose. Apparently, any known backdraw device may be combined with the above arrangement if desired for some kinds of yarn without detracting from the advantages of the inventive arrangement including the reduction inamount of the back draw and in pressure of air forming jets.

In the above, various advantages of the present invention have been described which are obtainable with air jet looms. Description will now be made on further advantages of the present invention which are obtainable with air or water jet looms and those employing auxiliary air blasts in addition to the main nozzle to aid the picking operation.

At first, description will be made in connection with the yarn measuring device. In general, that portion of the weft yarn inserted which extends between a point close to the selvage adjacent to the main air nozzle and the measuring device is subjected to an unusually high tension after the weft has been closely interlaced with warp yarns. To avoid this, the weft yarn is usually cut with scissors before it is tensioned, or is drawn back in advance so as to be freely battened. In some cases, the measuring device is designed so that the weft can Slip over the periphery of the measuring drum. These known measures, however, are all not entirely satisfactory. In some instances, the time of scissor cutting cannot be freely advanced because of the type of loom, kind of fabric, timing of the beat-up operation, or other factors. Also, the drawing back of the inserted weft involves some problems in the other aspects of the weaving operation, as described hereinbefore. Weft slippage on the measuring device tends to detract from the measuring accuracy. In case the weft yarn is cut under substantial tension, there is a danger that the cut end portion of the weft be retracted excessively into the nozzle to the extent normal nozzle pressure will not recover the weft and necessitating an additonal pressure for the subsequent picking operation. According to the present invention, which overcomes the above diticulties, any required weft increment is taken from the measuring device without causing any excessive tension in the weft and without use of any means causing resistance to the flight of the next weft. The measuring device according to the present invention is of the general type including a rotating drum about which weft yarn is wound for measurement, but the feature is that the rotating drum is constructed to have different diameters along its axial length. As shown in FIG. 7, one form of the inventive measuring device includes a shouldered rotating drum having cylindrical sections of different diameters and a plurality of pressure rollers operable to engage the respective drum sections in a timed relation to each other to deliver a length of weft yarn required to form a pick, as will be described hereinafter in detail. This form of measuring device is advantageous in that it enables adjustment of the yarn feed within a limited range and that it makes constant the rate at which yarn is paid out from the cone and the tension under which it is wound about the measuring drum, alleviating the need for any substantial accuracy in the configuration and nature of cones.

Referring again to FIG. 7, the measuring drum 2 is continuously driven from the main drive shaft of the loom and is shouldered to dene cylindrical sections 2x and 2y, one of which sections 2x having a circumference larger than that of the other section 2y. Small rollers 14 and I4 are arranged to engage the respective drum sections 2x and 2y in any desired timed relation to each other to deliver weft yarn 4. The yarn 4 is paid out from the cone 1 to pass through a yarn guide 16 and between one of the drum sections 2x and roller 14 and further through yarn guides 15 and 16' to pass between the other drum section 2y and associated roller 14. The yarn then passes through a further yarn guide 15 to be wound about the drum by engagement with a retractable pin 12. The retractable pin 12 is in its retracted position within the drum during weft ejection to allow the weft to be introduced through guide 17 into .the nozzle 3. FIG. 8 illustrates the manner in which rollers 14 and 14" are disengaged from the respective drum-sections 2x and 2y. The roller 14 is carried on a lever 19 fulcrumed at 18. The lever 19 is biased in a counterclockwise direction as viewed in FIG. 8 by a spring 23 into contacting engagement with a cam 20 as at 22.Y The cam 20 has a raised portion 21 and is driven by the main shaft of the loom for rotation in direct proportion with the crank motion. As the cam 20 rotates, its raised portion 21 actuates the lever 22 so that roller 14 thereon is disengaged from the drum section 2y. It will be apparent, therefore, that the time when the roller 14 is brought into pressure contact with the drum section 14 and the time period during which the roller 14 is held in such Contact therewith can be controlled by varying the shape of the raised cam portion 21. The same relationship is also held between the drum section 2x and roller 14. Description will now be made on the operation of the measuring device with reference to FIG. 7. Assume that the two rollers are held in pressure contact with the respective drum sections for the same period of time. Then, the roller 14 acts to deliver a larger length of yarn than roller 14 since the former is associated with the drum section 2x having a larger diameter than the one 2y for the latter. In case the two rollers are both held in pressure contact with the drum for a portion of each cycle of operation of the measuring device, the yarn limb on the drum extending between yarn guides 15 and 16 is slackened to sag as indicated by the broken line 4. This slack yarn can readily be fed forwardly by moving the roller 14' apart from the drum section 2y. It is to be noted, therefore, that the weft yarn inserted through the warp shed can be kept free from any excessive force and hence from recoiling when cut under such tension, if the roller 14 is only released, when the weft yarn is tensioned upon battening, to allow the slack weft 4 to be drawn forward as required, and the picking operation can thus be effected eiciently without any mispick even by use of a jet of air at low pressure. Next, where it is arranged so that the roller 14 is continuously held in pressure Contact with the drum while roller 14 is released therefrom at an appropriate time during each cycle of machine operation, `the weft yarn around the drum is at all times held in a slack state between the yarn guides 15 and 16'. With such arrangement, it will be recognized that any irregularity in tension of the yarn being wound on the measuring drum, occurring due to insufficient yarn release from the cone, and the resulting nonuniform yarn delivery from the measuring drum frequently found with previous measuring devices, are effectively eliminated to enable smooth and accurate yarn measurement even in cases where yarn cones are not made in an elaborate form.

Further, any desired length of yarn can be measured by arranging so that .the weft yarn is initially delivered solely under the action of roller 14 with roller 14 held apart from the drum and then solely under the action of roller 14 with roller 14 held apart from the drum. In other words, the measured length of yarn can be finely adjusted within a limited range simply by controlling the timing of engagement and disengagement of the two rollers with the measuring drum independently of each other. The measuring purpose can be attained by use of either roller 14 or 14 alone if only separate means are provided to release the tension of the pick for the battening operation. The shouldered configuration of the measuring drum is intended to enable control of the yarn length measured for each pick, as will be readily understood. When it is desired to vary the depth of the drum shoulder or the diameter of either drum section 2x or 2y, it is recommendable to prepare one or more annular belts as indicated at 66 in FIG. 9a or one or more pairs of arcuate straps 67 in FIG. 9b, which can be detachably fitted over the cylindrical drum sections when required and use of which belts or straps makes it extremely easy to measure different lengths of yarn. It will be understood that the same effect can also be obtained by use of two separate eters which are rotatable at the same speed or by employing two angularly displaceable rollers on a shouldered drum similar to the one used in the first form of measuring device.

A further form of measuring device, which includes a frusto-conical drum, will next be described with reference to FIGS. 10 and 11. In these figures, reference nuameral 101 denotes a hollow rotating drum having a conically shaped peripheral surface; a feed roller 102 arranged to engage the drum end portion having a larger diameter; and a retractable operating pin 103 arranged in the other drum end portion to extend radially outwardly through the adjacent peripheral wall of the drum. A hollow bearing boss 104 is secured to the adjacent end wall of the drum in alignment therewith and journaled in the machine frame (not shown) by way of a bearing 105 to allow the drum to rotate freely. A gear 106 is rsecured to the boss 104 and is'in mesh with another gear 103 mounted on a rotative shaft 107, which is driven from the main shaft of the loom. The ratio of the number of teeth of gear 106 to that of gear 107 is l to 2 so that the drum 101 driven at a rotative speed twice as high as that of the main shaft of the loom. A bracket 109 is secured to the inside of the adjacent end wall of the drum in the vicinity of the operating pin 103 and pivoted to the bracket is a bellcrank lever 110 one end of Which is pivotally connected to the inner end of the operating pin. The other end of the bellcrank lever 110 is pivotally connected to the inner end of a rotative shaft 111 extending through the boss 104. A lever 112 is fulcrumed intermediate its ends as at 113 to the machine frame and carries at opposite ends balls 114 and 115, which are fitted in respective grooves formed in annular members 114' and 115 secured to the rotative shafts 107 and 111. The width of the groove formed in the annular member 114 is considerably larger than the associated ball 114, which is held at all times in contact with one side wall of the groove under the bias of a spring 116 secured at one end to the lever 112. A cam 117 is formed on one side wall of the groove, in annular member 115 to act upon the ball 115 thereby to rock the lever 112 against the bias of spring 116 and move the shaft 111 axially to the left. As the result, the operating pin 103 is withdrawn by bellcrank lever 110 to the inside of the drum wall. As the ball 115 passes over the cam 117, the lever 112 and associated parts are restored to their normal position under the bias of spring 116 causing the operating pin 103 to project beyond the peripheral wall of the drum. The operating pin 103 is held in this advanced position until the cam 117 comes again into engagement with the ball 115.

Weft yarn 4 coming from the cone 1 passes through yarn guides 122 and 123 and between the roller 102 and the adjacent drum surface and, turning about the drum periphery comes into engagement with the operating pin. The yarn further proceeds through a yarn guide 125 to be fed into the air nozzle 3 as air is ejected therethrough.

1n operation, the drum 101 is continuously driven at an angular velocity twice that of the main shaft of the loom, as described hereinbefore, and the roller 102 is continuously held in pressure contact with the drum so that the weft yarn extending therebetween is pulled out from cone 1 to be wound about the peripheral surface of the drum. The time when an appropriate length of weft yarn has been wound about the drum is approximately the same as the time when au appropriate shed or funnel of warp yarns has been formed to allow the nozzle to eject pressure fluid. When the nozzle ejects fluid under pressure, cam 117 comes into engagement with the ball 115 to retract the operating pin 103 into the drum allowing the weft wound about the drum to be released therefrom to be fed into the air nozzle 3. Such delivery of weft yarn continues until the drum has made just two complete revolutions. When the cam 117 is moved past the ball 115, the pin 103 again projects beyond the drum surface to engage the next length of weft, preparing for the next cycle of the above sequential operation. The weft yarn on the drum tends to slack between the feeding region of the drum contacting the roller 102 and the pin 103 because the feeding region has a radial distance larger than that of the point of intersection of the pin 103 with the drum surface. This slack of weft effectively accommodates any variation in tension of the yarn due to non-uniform delivery from cone 1 while allowing the weft on the drum to be smoothly released therefrom without encountering any resistance.

Another form of measuring device shown in FIGS. l2 and 13 has means for adjusting the amount of slack yarn. In this embodiment, the peripheral wall of the drum has an axially elongated slot 130, through which pin 103 extends. Slotted bars 131 and 132 are secured to the adjacent inner wall surface of the drum and the upper arm of the bellcrank lever 110, respectively, by screw means. The pin 103 is pivoted at its bottom to one of the slotted bars 132 and extends through a small aperture formed in the other slotted bar 132 to project beyond the drum surface. The yarn guide 124 is carried on a rod which is secured to the machine frame by way of a slotted adjusting piece 133, as shown in FIG. 13. In case the slack of weft yarn is excessive, it can be reduced by displacing slotted bars 131 and 132 and hence pin 103 toward the base end of the conical drum by an appropriate distance to increase the radial dis tance of the drum surface adjacent to the pin 103 so that the latter rotates at an increased peripheral speed while engaging the weft. In this case, it is to be understood that the yarn guide 124 also is shifted toward the base end of the conical drum by means of the adjusting piece 133. Contrarily, if the pin 103 and yarn guide 124 are shifted toward the reduced end portion of the drum, the peripheral speed of the drum surface adjacent to the pin is reduced thereby to increase the amount of slack. FIG. 14 illustrates a modification of the measuring drum, which includes a cylindrical section 101' for engagement with the feed roller 102 and the remaining section which is frusto-conical. This form of measuring drum with the roller 102 mounted on an axis parallel to the axis of the drum affords some manufacturing convenience but is substantially the same in functional effect as the previously described forms. A proposal has already been made to employ a conical drum and a feed roller cooperable therewith and adjustable in position along the drum surface to vary the measured length of yarn, which is carried by a running member to be fed to the air nozzle.

It will be apparent that the same principle may also be applied to the measuring device of the present invention having a conically shaped measuring drum by employing a feed roller adjustable in position along the drum surface for varying the yarn feed or the measured length of yarn to be fed to the air nozzle.

As apparent from the foregoing description, the measuring device according to the present invention, which has been illustrated in various forms, is advantageous in that there exists at all times a tendency of the weft yarn on the drum to slack between the feeding region of the drum surface contacting the feed roller and the operating pin projecting radially outwardly beyond the drum surface, enabling the device tomeasure weft smoothly without subjecting it to any excesssive tension when it is wound about the drum and released therefrom. In addition, the slack of yarn is effective to alleviate any excessive tension of the weft otherwise occurring when it is beaten up and to impart a proper tension to the weft when cut thereby to completely prevent problems caused by the recoiling of the cut end of weft.

A further feature of the present invention is a nipper device arranged between the weft ejecting nozzle and the scissors, as at 5 in FIG. 1. The provision of the device has a great influence upon the pressure of air used for weft ejection.

If the weft end at the nozzle, ready to ily with the next jet of air, extends beyond the nozzle exit in excess, there is a danger that it might cling to the adjacent selvage of the fabric at the start of air ejection or be engaged oy the warp at the entrance of the shed of warp yarns. This clinging causes an unwanted delay of the insertion of the weft. This danger is serious particularly in the case where air ejection is started when the shed is still narrow. Therefore, the exit of the nozzle should be located considerably close to the selvage-forming warp, that is, the length of the weft end extending forwardly of the nozzle immediately before it is inserted should have an appropriate limited value. The danger that the weft end slip off the nozzle due to shock when the piek is cut is rather scarce if the weft inlet to the nozzle is spaced from the ejecting end thereof by a considerable distance, but, if this distance is excessively short, the weft end when icut by scissors tends to retract into the nozzle or Slip off the latter even Linder the slightest cutting shock. The weft retracted into the nozzle cannot have the desired or optimum initial speed of flight when ejected and higher air pressure is required to avoid such limitation to the initial `speed of the weft. It is to be understood that the distance between the weft inlet to the nozzle and the ejecting end thereof more or less depends lupon the type of nozzle as well as yarn used and thus in some cases cannot be extended to any satisfactory extent.

To overcome this difficulty, the present invention employs a nipper Vdevice between the nozzle and scissors which operates to grip the weft immediately before it is eut and release it immediately before ejection is started so that the weft extends forwardly of the nozzle opening over a predetermined distance at all times immediately before ejection is started. As shown in the drawings, the nozzle and the nipper or clamp device are arranged to move back and forth and the former further moves back and forth at weft ejection. With this arrangement, the nipper is not required to open wide since it does not interfere with the ejection of air if effected in a position slightly `apart from the clamp device. Also, the clamp device is not necessarily required to clamp the yarn so firmly depending upon the type of yarn used. This nipp-er device has an additional advantage that it eliminates any delay in weft flight due to misfunctioning of the scissors. With t-he jet loom according to the present invention, since weft is inserted by air at an extraordinarily low pressure, some delay in flight of the weft may be caused even when only a few filaments are life uncut, which would be blown off if high-pressure air be used. As shown clearly in FIGS. 15 and 16, the nipper device according to the present invention is arranged to retract with the end of the weft cut and gripped therein to completely clear the passage for the next flight of weft so that insertion of the weft can be effected satisfactorily even with low pressure air. Weft gripping means have frequently been used on previous shuttleless looms, but such means have included a structure which appears simple but actually involves various difficulties. Most of previous nipper devices have included a pair of members adapted to abut against each other to grip yarn therebetween under the resilience of a spring or like means and thus -have not been fully reliable because of the wear of the gripping members, vibration and ishock upon inter-engagement therebetween, and other factors. Such drawback of previous nipper devices is overcome by the present invention, as will be apparent from the following description made with reference to FIG. 15, which illustrates the gripping structure of the inventive device, and FIG. 16, which illustrates the manner in which it operates. In FIG. 16, reference character G indicates the position of the nipper device when the pick 1.1... is beaten up; and H its position when the shed of warp yarns is close to its maximum. A pair of nipper lingers 25 and 26 are formed of hard materials such as steel and hard nylon land are perfectly finished by face-to-face grinding. Fingers 25 and 26 are mounted on a pin 28 secured to a bracket 24 and are pressed against each other and against the adjacent face of the bracket 24 by a spring 27. One of the fingers 26 carries a lug 29, on which a sleeve 30 is moun-ted to freely rotate. A lever 31 has a bifurcated end formed to loosely embrace the sleeve 30 and is rockable back and forth `to swing the lingers 25 and 26 relatively to each other so that they cooperate to grip and release the weft extending from the nozzle 3. The lever 31 is fulcrumed as at 32 to the slay-sword 39 'and is held at the bottom in pressure lContact with a cam 35 under the bia-s of a spring 34. The cam 35 is driven at a speed directly proportional to the rotation of the loom crank. It will be understood that this clamp fingers 25 and 26 can readily be arranged to operate to engage the yarn at any required instant and remain effective for a required period of time by use of a cam 35 having a suitable proiile and a proper operational timing. The spring 27 should have a suitable spring rate in accordance with the `type of yarn and the speed of loom operation. The opposing edges of the clamp lingers 25 and 25 should obviously be slightly rounded so as not to form any sharp cutting edge. In place of employing spring 27, either one or both of clamp fingers may take the form of a magnet so that they are held at all times in sliding contact with each other. In this case, however, the strength of the magnet should be adjusted in .accordance with the type of yarn and the operational speed of the loom.

The clamp device of the present invention is not based upon the principle of collision and hence is completely free from shock. Use of clamp fingers 25 and 26 formed of hard material `and operable to lslide over each other is effective to eliminate friction and make the gripping action smooth and accurate, since the clampY fingers are held in close contact with each other for extended service life even if some friction exists therebetween. This clamp device is durable and reliable so that it is also usable for gripping the free end of the inserted weft at `a point adjacent the selvage remote from the air nozzle with ext-reme effectiveness. For example, the device can take an important role of stabilizing the free end of the inserted weft to control its tension, or making it possible to locate in the vicinity of the clamp -a suitable weft detector which is operable upon the basis of such weft tension. Such applications of the clamp device are not illustrated as they will be appa-rent to those skilled in lthe art.

A measure is known for releasably holding the weft end in front of the nozzle before ejection is started for the purpose of forming a loop of weft, which is effectively acted upon by the pressure of air ejected; the weft end being subsequently released. This measure, however, is entirely different in principle from the present invention and is rather detrimental to the inventive arrangement, in which weft is ejected into the shed of warp yarns when it is still narrow, as pointed out hereinbefore.

Description will now be made in connection with the arrangement for auxiliary blasts. Broadly, it has been known to use auxiliary blasts at points along the width of fabric. This can be realized in various ways, which may be broadly classified into two groups. In 4one group, air pressure is ejected in a continuous fashion, and in the other group it is ejected intermittently each time when required. The former group involves a number of problems in addition to the excessive loss of energy. First, it causes the weft to tremble to the last moment when it is beaten up, for example, when it is extremely small or is a twisted long fiber yarn, and the marginal portion of the fabric remote from the ejecting nozzle often has a con-struction including weft slacks. To avoid this, it is required to reduce the strength of l2 auxiliaryblasts toV a substantial extent or interrupt them shortly before the weft is beaten up. Such interruption of auxiliary blasts, however, involves a great ditiiculty due to low air pressure and the distance between the auxiliary nozzles and the control valve for their interruption. Intermittent ejection forms air blasts which are really pulsating under a pressure much lower than that at the control valve, since the air pressure when the valve is opened must iirst flow against the resistance of pipe walls to fill the line extending from the valve to the auxiliary nozzles before it is ejected. Therefore, the air pressure upstream of the valve must have a value a number of times as high as the pressure level required at the nozzles, and this apparently results in an enormous energy loss. In order to overcome this deficiency with use of a low air pressure source, which reduces the cost of the system, it is necessary to use a piping of substantial diameter for interconnecting the valve Iand auxiliary nozzles and to minimize the distance of the valve therefrom. To do this, the valve must be located in the region of the reed frame. This valve arrangement has great advantage from the manufacturing standpoint since slight leakage of air through the valve is permissible. Under this condition, it is apparently easy to obtain a valve operable at high speed. The auxiliary blast arrangement according to the present invention will next be described with reference to FIGS. l, 17 and 18. As illustr-ated, the top and bottom reed frames 6 and 6 are made hollow to serve as an air reservoir and4 associated piping and are filled with air under pressure directed through conduit 57. Arranged in the reed frames 6 and 6 are respective bars 46 and 46 which are formed with or to hold auxiliary blast nozzles 8 and 8', respectively. Slide plates 47 and 47', slidably arranged on the bars 46 and 46', respectively, lare formed with .small apertures 58 and 58 and can be adjusted so that the apertures 58 and 53 are selectively positioned in or out of alignment with the nozzles 8 and 8 to allow air to iiow therethrough or to interrupt or greatly reduce such air liow, as required. The sliding contact between the bar 46 or 46 and the slide plate 47 or 47 is made close in the regions of the nozzles and -cooperating Iapertures but in the remaining regions they are preferably slightly spaced apart from each other. The bars and slide plates should be made of a material which does not require frequent oiling. Rods 48 and 48 are connected to the adjacent ends of the slide plates 47 and 47 and extend outwardly through the adjacent end walls of the hollow reed frames 6 and 6', respectively, to carry rollers 49 and 49. Cams 50 and 50 are provided to drive respective rollers 49 and v49 right and left, rollers 49 and -49 being held in pressure contact with respective cams under the bias of springs indicated at 61 and 61', respectively, in FIG. 1. A bevel gear 60 is secured to the shaft I54 described hereinbefore to cooperate with another -bevel gear 59, which is secured to a vertical shaft 51 supported by bearings 52, 52 and 52". As the shaft 51 rotates with cams 50 and 50 mounted thereon, the raised portions of the cams actuate respective rollers '49 and 49. The timing and duration of the auxiliary blasts can thus be controlled by adjustment of the circumferential position and extent of the raised portions of respective cams 50 and 50'. It is preferable that the auxiliary nozzles are arranged for limited lateral and back and forth movement as is often required with reeds of different densities.

It is to be understood that the auxiliary blast device is not limited t-o the illustrated arrangement but may be constructed and arranged in various manner-s as long as it is arranged in the region of the reed frame for back and forth movement therewith and the blasts are periodically interrupted during such movement.

Yet another important feature of the present invention lies in the provision of a shielding device for preventing dissipation of the air stream formed in the warp shed. Use of such shielding device on air jet looms has been linown per se, but any of previous shielding devices cannot be used with success on jet looms employing low pressure air as used in the present invention. Conventional devices have only included screens or shield plates secured to the top and bottom members of the reed frame close to the opposing edges thereof, as indicated at 64 and 64.- in FIGS. 19E and 19]. The length of such shield plates and particularly of the upper one as measured in the direction of warp cannot exceed about half the length of the reed stroke, since if made longer the leading edge of the shield plate would engage and push down the surface of the woven fabric during the forward motion of the reed thus causing damage thereto. if the plate be shifted slightly upwardly to avoid such damage, it would not serve the purpose because of its distance from warp yarns.

According to the present invention, a exible and slightly resilient sheet, for example, made of soft plastic, is attached to the warp side of each of the screens or shield plates, which are of the conventional type, for the purpose of substantially completely shielding the warp shed on its top and bottom sides.

Referring to FGS. 191 and 19], reference numeral It? designates warp yarns which are shed by heddles 63 and 63' to form a weft passage or shed 68. As illustrated, the screens or shield plates 64 and 6d. are secured to the front sides of the top and bottom members 6 and 6 of the reed frame so as to extend along the warp yarns when the shed is at its maximum, and each has a length about half the reed stroke. The flexible and slightly resilient sheet members 65 and 65', for example, made of vinyl chloride have their rear edges secured to the inside of the respective shield plates 64 and 6ft in a manner so that the sheet members extend forwardly beyond the respective shield plates. When the shed is at its maximum as shown in FIG. l9, the flexible sheet members extend along the warp yarns to the vinicity of the beating line and thus together with the screens 64 and 64 cover the warp yarns substantially completely on the top and bottom sides thereof so that dissipation or scattering of the ejected air is prevented. As the reed frame approaches the beating line, as shown in PEG. 19], the upper sheet member b is bent gently along the upper surface of the woven fa'bric without causing any damage thereto. In the illustrated embodiment, flexible sheet members are secured to the upper and lower screens, as described and shown, the flexible member 65 on the lower screen 6d does not come into contact with the fabric surface even if it be arranged close to the warp yarns at the maximum of shed and may itself be extended to the vicinity of the beating line instead of securing flexible sheet o5' thereto. Also, the screens 64 and 64' are not necessarily made entirely solid but their portions overlapping sheet members 65 and 65 may be made foraminous or latticed if desired.

As apparent from the foregoing, the shielding device of the present invention is formed so as to cover the Warp shed at all times substantially completely thereby to prevent dissipation of ejected air and thus has an advantage that consumption of air pressure is substantially reduced. This is important particularly on looms in which low pressure air is used to form jets each continuing for a relatively long period of time. An additional advantage of this shielding device is that, since air is not allowed to flow vertically through the spaces between the adjacent warp yarns, the weft yarn is effectively kept from being flexed in flight and its end can never present itself through or between the adjacent warp-s; thus ensuring smooth insertion of the weft through the shed of warp yarns.

it will be appreciated from the foregoing that the present invention has solved all of the problems pointed out hereinbefore and relating to the use of low pressure air for weft insertion, including provision of an optimum lll arrangement for auxiliary air blasts, extension of the air ejecting time, prevention of the ejected weft from contacting warp yarns, and elimination of shock and resistance to the weft in iiight. According to the present invention, therefore, the range of yarns weavable into fabric is extremely widened including tine ones which have been unweavable on conventional jet looms; weaving operation can be per-formed eiciently and with comfort causing no unpleasant explosive sounds which occur with use of high air pressure. The loom according to the present invention is also highly advantageous from the standpoint of energy cost since it employs air at a pressure of about one-third to one-fifth the pressure of air previously used in the art.

What is claimed is:

i. A yarn measuring device for a shuttleless loom comprising a measuring drum, a feed roller cooperable therewith to pull out weft yarn and a yarn catching pin arranged to wind the said weft yarn about the said measuring drum and to be retracted within the measuring drum at a pin-retracting point during weft ejection movement to allow the weft to be introduced into a shed, a yarn payed-out point forme-d by the contact `of the said yarn measuring drum and the roller, said yarn payedout point being radially further distant from the axis of the measuring drum than is the pin-retracting-point at the surface of the measuring drum whereby the speed of the yarn fed by said feed roller and drum is faster than the speed of the portion of the yarn caught by said catching pin so that slack is introduced in the portion of the yarn between said yarn payed-out point and said catching pin.

2. A jet loom of the type including a reed movable between forward and rearward positions, a Huid nozzle for inserting a weft along a path into a shed formed of warp yarns, said jet loom further comprising means for moving said fluid nozzle along the warp in a rectilineal path in association with the beat-up movement of the reed while maintaining the direction of the axis of said nozzle in a manner so that the distance between the axis of said nozzle and the plane of the reed is varied during each cycle of operation.

3. A jet loom as set forth in claim 2, said uid nozzle being adapted so that a weft yarn is ejected through said fluid nozzle along a path offset from the axis of said fluid nozzle toward the reed.

4. A jet loom as set forth in claim 2, wherein said duid nozzle is arranged adjacent one selvage of the fabric being woven, said jet loom further comprising a weft severing means positioned between said fluid nozzle and the adjacent selvage, a weft clamping device arranged between said duid nozzle and said weft severing means, means for moving said weft clamping device back and forth relative to the movement of said uid nozzle so as to clear the path of weft insertion at the time when a weft yarn is inserted into the shed, said weft clamping device `being operable to clamp the weft yarn immediately before it is cut by said weft severing means and to release the weft yarn immediately before it is inserted into the shed by said fluid nozzle.

5. A jet loom as set forth in claim 2, wherein the fabric being woven on the loom has a plurality of selvages, said jet loom further comprising a weft clamping device movable in front of said fluid nozzle, said weft clamping device being positioned outside of and adjacent to at least one of the plurality of selvages, said weft clamping device comprising a pair of clamp fingers made of hard finished material, biasing means for moving said clamp fingers in sliding contact with each other, said clamp fingers being slidable relative to each other in a plane substantially at right angles to the direction in which the weft is inserted so that said fingers can clamp and release the weft.

6. A jet loom as set forth in claim 5, wherein said means for biasing comprises spring means.

7. An air jet loom as claimed in claim 2 having a shielding device for continuously shielding most portions of the shed formed of warp yarns to prevent dissipation of air ejected therein, said shielding device including planar screens arranged on the top and bottom sides of the shed and a flexible slightly resilient sheet member secured to at least one of said planar screens.

8. An air jet loom as set forth in claim 7, wherein said planar screens are solid.

9. An air jet loom as set forth in claim 7, wherein said planar screens are perforated.

10. A yarn measuring device for a loom and of the type including a measuring drum arranged to be driven inrsequence with the loom, roller means arranged to make pressure contact with said measuring drum for drawing a weft yarn in a manner so that it is wound albout said measuring drum, said device being characterized in that said measuring drum includes cylindrical sections of different diameters and said roller means includes a plurality of feed rollers arranged to make pressure contact with said respective drum sections so as to draw the weft yarn at different speeds and means for alternately moving said feed rollers out of pressure contact with said respective drum sections but always leaving at least one roller in pressure contact with its respective section so that the length of yarn measured for each weft insertion and the yarn tension can be selectively controlled.

11. A yarn measuring device as set forth in claim 10 wherein said measuring drum is conical.

12. A yarn measuring device as set forth in claim 10, wherein said measuring drum is shoulder-shaped.

13. A jet loom of the type including a reed adapted to move in a beating-up motion, a fluid nozzle positioned `forward of said reed, means for moving said uid nozzle in a rectilineal path toward and away from said reed in relation to the beating-up movement of said reed, said fluid nozzle having a yarn inlet aperture formed on its rearward side facing said reed, and a yarn guide means located rearwardly of the axis of said nozzle, a yarn measuring device for feeding weft yarns to said nozzle in a predetermined amount, said yarn guide means guiding said weft yarns fed from said yarn measuring device to said yarn inlet aperture.

14. An auxiliary air blast device for an air jet loom of the type having a reed frame and a main air nozzle for inserting a weft into a shed formed of warp yarns, said auxiliary air blast device comprising auxiliary nozzle means positioned on the reed frame for directing auxiliary jets of fluid along the path of insertion to aid the ight of the weft yarn as ejected through the main air nozzle, air conduit means for feeding air to said auxiliary nozzle means, and means provided on said reed frame adjacent to the points where said air conduit means cornmunicates with said auxiliary nozzle means for intermittently interrupting the air ow between said air conduit means and said auxiliary nozzle means.

References Cited by the Examiner UNITED STATES PATENTS 1,721,940 l/1929 Ballon 139-127 2,668,560 2/1954 Svaty 139-127 FOREIGN PATENTS 655,672 1/1963 Canada. 1,040,379 5/1953 France. 1,261,463 4/1961 France.

DONALD W. PARKER, Primary Examiner.

H. S. JAUDON, Assistant Examiner. 

2. A JET LOOM OF THE TYPE INCLUDING A REED MOVABLE BETWEEN FORWARD AND REARWARD POSITIONS, A FLUID NOZZLE FOR INSERTING A WEFT ALONG A PATH INTO A SHED FORMED OF WARP YARNS, SAID JET LOOM FURTHER COMPRISING MEANS FOR MOVING SAID FLUID NOZZLE ALONG THE WARP IN A RECTILINEAL PATH IN ASSOCIATION WITH THE BEAT-UP MOVEMENT OF THE REED WHILE MAINTIANING THE DIRECTION OF THE AXIS OF SAID NOZZLE IN A MANNER SO THAT THE DISTANCE BETWEEN THE AXIS OF SAID NOZZLE AND THE PLANE OF THE REED IS VARIED DURING EACH CYCLE OF OPERATION. 